As is well known, commonly employed air conditioning systems operating on a vapor compression cycle utilize evaporators as a means of cooling tee air to be conditioned. A refrigerant is flowed through an evaporator and expanded therein. In so doing, it absorbs its heat of vaporization, thereby cooling the medium with which it is in contact, typically heat exchanger tubes. The air to be conditioned is flowed over those tubes (which typically will be provided with fins for improved heat transfer). The air, at least locally, will be cooled below its dew point with the result that water will condense out of the air on the fins and on the tubes. This condensate must be removed or else it will freeze and plug the air flow path.
A variety of proposals for condensate removal have evolved and in their simplest form, involve the use of gravitation forces with a possible assist from the velocity of the air stream moving through the evaporator. These systems work rather well but frequently are bulky.
Furthermore, where relatively high velocity air streams may be present as, for example, in vehicular air conditioning systems where fans operate at high speed to achieve maximum cooling in a short period of time, it is desirable to remove the moisture from the evaporator as quickly as possible to prevent it from being entrained in the air stream and entering the passenger compartment of the vehicle. Furthermore, it is desirable, in order to obtain fuel economy, that the means employed to collect condensate weigh as little as possible. It is also desirable that the bulk of the same be absolutely minimized.
Furthermore, and equally importantly, it is desirable to provide a means whereby condensate is conducted away from the heat exchange surfaces of the heat exchanger so as to prevent condensate films from interfering with efficient heat transfer.
The present invention is directed to obtaining the above objects.